,
Francisco Rowe [aut]| Title: | Summary Statistics for Geospatial Features |
|---|---|
| Description: | Provides summary statistics of local geospatial features within a given geographic area. It does so by calculating the area covered by a target geospatial feature (i.e. buildings, parks, lakes, etc.). The geospatial features can be of any type of geospatial data, including point, polygon or line data. |
| Authors: | Nikos Patias [aut, cre] ,
Francisco Rowe [aut] |
| Maintainer: | Nikos Patias <[email protected]> |
| License: | MIT + file LICENSE |
| Version: | 1.0.4 |
| Built: | 2024-11-06 03:27:08 UTC |
| Source: | https://github.com/patnik/extratum |
Computes three different summary statistics:
(1) TotalArea total area of each polygon;
(2) AreaCovered area covered by a multipolygon object within a high order polygon; and,
(3) Ratio ratio between AreaCovered and TotalArea i.e.
ratio between an area covered by a given set of features and total area of a higher-order geography polygon.
areal_calc(polygon_layer, higher_geo_lay, unique_id_code, crs)areal_calc(polygon_layer, higher_geo_lay, unique_id_code, crs)
polygon_layer |
multipolygon object of class |
higher_geo_lay |
multipolygon object of class |
unique_id_code |
a string; indicating a unique ID column of |
crs |
coordinate reference system: integer with the EPSG code, or character based on proj4string. |
The function requires two sets of polygon data: high-order and low-order geographic polygons
a tibble data frame object containing four columns is returned:
the unique_id_code of higher_geo_lay
the total area of each polygon
in higher_geo_lay (TotalArea),
the total area covered by polygon_layer features (AreaCovered),
the ratio between the total area covered by polygon_layer and total area of
higher_geo_lay polygon (Ratio).
## Run areal_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: #outcome <- areal_calc(polygon_layer = pol_small, #higher_geo_lay = pol_large, #unique_id_code = "large_pol_", #crs = "epsg:27700") ## End(Not run)## Run areal_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: #outcome <- areal_calc(polygon_layer = pol_small, #higher_geo_lay = pol_large, #unique_id_code = "large_pol_", #crs = "epsg:27700") ## End(Not run)
Computes three different summary statistics:
(1) TotalArea total area of each polygon;
(2) TotalLength total length of a multilinestring object within a polygon
(3) Ratio ratio between TotalLength and TotalArea i.e.
the ratio between the total length and total area of a higher-order geography polygon.
line_calc(line_layer, higher_geo_lay, unique_id_code, crs)line_calc(line_layer, higher_geo_lay, unique_id_code, crs)
line_layer |
multilinestring object of class |
higher_geo_lay |
multipologon object of class |
unique_id_code |
a string; indicating a unique ID column of |
crs |
coordinate reference system: integer with the EPSG code, or character based on proj4string. |
a tibble data frame object containing four columns:
the unique_id_code of higher_geo_lay
the total area of each polygon
in higher_geo_lay (TotalArea)
the total length of line_layer features (TotalLength)
the ratio between the total length of line_layer and the the total area of
higher_geo_lay polygon (Ratio).
## Run line_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: #outcome <- line_calc( # line_layer = lines, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # crs = "epsg:27700") ## End(Not run)## Run line_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: #outcome <- line_calc( # line_layer = lines, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # crs = "epsg:27700") ## End(Not run)
Toy dataset of line data.
lineslines
A geospatial file of six lines georeferenced in wgs84.
Own dataset.
Computes three different summary statistics:
(1) TotalArea total area of each polygon;
(2) NoPoints number of multipoint objects within a given polygon; and,
(3) Ratio ratio between NoPoints and TotalArea covered within a polygon.
point_calc( point_data, higher_geo_lay, unique_id_code, class_col, crs, total_points = TRUE )point_calc( point_data, higher_geo_lay, unique_id_code, class_col, crs, total_points = TRUE )
point_data |
multipoint object of class |
higher_geo_lay |
multipolygon object of class |
unique_id_code |
a string; indicating a unique ID column of |
class_col |
a string; indicating a column name for |
crs |
coordinate reference system: integer with the EPSG code, or character based on proj4string. |
total_points |
logical; if the target is to measure the total number of points set to |
The function requires two sets of data: a layer of geographic polygons, and a layer of points
If points have been categorised into classes, the function can return the same summary
measures for each class if total_points = FALSE by specifying the column that contains the classification in class_col
if total_points = TRUE:
A tibble data frame objects containing four columns is returned:
the unique_id_code of higher_geo_lay
the total area of each polygon
in higher_geo_lay (TotalArea)
the total number of point features point_data (NoPoints),
and
the ratio between the total number of point features point_data and the the total area of
higher_geo_lay polygon (Ratio).
if total_points = FALSE:
A list of three tibble data frame objects is returned.
The object PointsLong contains three columns:
the unique_id_code of higher_geo_lay, the class_col of point_data,
the number of point features point_data by class (NoPoints), the total area of each polygon
in higher_geo_lay (TotalArea) and the ratio between the number of point features by class point_data
and the the total area of higher_geo_lay polygon (Ratio).
The object PointsCountWide:
Returns the point counts of PointsLong by unique_id_code and class_col in a wide format.
The object PointsRatioWide:
Returns the ratio of PointsLong by unique_id_code and class_col in a wide format.
## Run point_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: ## This example returns the total points count and ratio # outcome1 <- point_calc( # point_data = points, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # crs = "epsg:27700", # total_points = TRUE) ## This example returns the points count and ratio by class # outcome2 <- point_calc( # point_data = points, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # class_col = "class_name", # crs = "epsg:27700", # total_points = FALSE) ## End(Not run)## Run point_calc() using the packages' dummy data sets. ## The data sets are georeferenced on wgs84. However, a planar system is used to measure areas. ## For the examples provided here, points and polygons relate to the United Kingdom. ## So the British National Grid is used. ## Not run: ## This example returns the total points count and ratio # outcome1 <- point_calc( # point_data = points, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # crs = "epsg:27700", # total_points = TRUE) ## This example returns the points count and ratio by class # outcome2 <- point_calc( # point_data = points, # higher_geo_lay = pol_large, # unique_id_code = "large_pol_", # class_col = "class_name", # crs = "epsg:27700", # total_points = FALSE) ## End(Not run)
Toy dataset of point data.
pointspoints
A geospatial file of ten points georeferenced in wgs84.
Own dataset.
Toy dataset of polygon data.
pol_largepol_large
A geospatial file of three polygons georeferenced in wgs84.
Own dataset.
Toy dataset of polygon data.
pol_smallpol_small
A geospatial file of eight polygons georeferenced in wgs84.
Own dataset.